Large monster movement

Q: If the movement of a large monster is interrupted (e.g: with caltrops) and there is no space to "expand" it, how do you proceed?

A: You cannot interrupt large monster movement in a space in which it cannot expand. (1)

Q: How does interrupting movement to attack interact with large monster movement?

A: When moving with a large monster, you always choose 1 space it occupies to count movement. If you interrupt movement to attack, you choose any space it occupies to continue movement. This could result in additional spaces moved during the movement. (1) (2)

Q: May large monsters interrupt a move action with another action (e.g., open door, attack) after hey have shrunk to 1x1 but before they have spent a movement point so that they can expand in a direction different than their orientation before the move action? See post for description of proposed mechanic: (1)

A: Allowed! (1)

Q: How to treat large monsters, when reduced to 1x1 during their movement - especially in context of pit spaces: If a “shrunken” large monster enters a pit space, does it suffer 2 damage and ends its movement or is it totally immune to the pit spaces while moving?

A: As written, a large monster whose movement is in process is not affected by pit spaces and can move through them as normal. (1)